Quentin, The only case that I've seen where there is a regular offset of about 5-10mV is when the device is set to make a measurement where the AINN input is tied to AVSS (or ground on a unipolar supply). In that case, the input is outside the PGA's range of operation. However, I'll answer your questions: 1. The die for the ADS1246 , ADS1247 , and ADS1248 is the same. However, we are able to program the functionality for the die. At production, we're able to enable and test different features of the device. 2. I think it's very unlikely that the IDAC could be initiated and cause a current leakage. Like the other features, by setting the device to be an ADS1246 , certain functions are automatically disabled or set. To test this, you could disconnect the sensor excitation and short out your sensor with an ammeter just to see if there is extra current coming out of the input pin. Also you could try to program into the register space normally reserved for ADS1247 and ADS1248 , but I've never tried this and I would guess that that section is locked out. However, I don't think that IDAC current is the likely problem. Because the error comes up intermittently, I'd look for a different source of error. If you have a schematic, device configuration, and a description of your system and the error, I could review it and see if there's anything that might be a problem. Joseph Wu
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